Electric steam boiler



July 26 1927.

E. SCHLECK I ELECTRIC STEAM BOILER Filed Jan. 16. 1926 v R 1 1| an 4 kg. k

|ll| H HHU ll. 0/04 I F a m Passed July. 26, 1927.

UNITED STATES R'A TENT OFFICE.

nnunm scnmcx, or BERLIN, enmlm.

mc'rnic srnm 301mm I Application filed January 1s, m, Serial Io. gun, and in Germany October a, 11m.

' This inventionrelates to a boiler electrically heated after the electrode principle and comprising steam generating apparatus, the inner electrode of which dipping into the 5 liquid contained in the outer electrode and designed to be heated. In boilers of this type working polyphase current the voltageof each of the three phases is neutralized or converted into heat in only one steam generator. The necessity of neutralizing the voltage in only one steam generator makes the regulating of' the efficiency extraordinarily diflicult, especially at higher voltages,

as these require along resistance distance towards all sides. The necessary long resistance distances can however only be ob-1 tained by correspondingly lengthening of the diameter and enlargement of the liquid reservoir which forms the outer electrode.

\ Asthe efliciency increases with the cross section of the liquid, the efficiency cannot be decreased beyond a certain degree owing to the very great liquid cross section and to the, very high voltages. It has been proposed to reduce the li uid cross section by displacement of the i uid by means of insulating bodies of porce ain or the like inserted into the outer electrode, in order to reduce thus the efliciency to the desired degree, but very 80 large expensive and heavy porcelain bodies are required whereby the cost of installation is increased so" much that in many cases it is impossible to use these means. v

For extraordinarily high voltages, for instance 10,000- volts, the apparatus which forms .the outer electrodes are of very great dimensions and weight which renders the whole unpractical. A further fact to be taken into consideration is that liquid receptacles of this size cannot be inserted as a whole through the manhole but in different pieces to be put together in the boiler whereby the building up of the plant is rendered more diflicult. The invention consists essentially in that the voltages of each of, the phases are not neutralized in one steam generator only, but

in several series-connected steam generating apparatus wherefrom results the great advantage that the diameter of the steam generator is considerably reduced as the inner' electrodes can be made to dip more deeply into the liquid in the outer cup-shaped electrodes, the desired. efiect being not pui- 1 which .duced only by the ends of the inner electrodes but by the entire muchlonger submerged portion of said inner electrodes.

The efliciency can be regulated in very wide I limits by re ulating the liquid level accordingly, the e ciency being less great at a low liquld level and greater at higher liquid level. This is the same in the sin le generator system, but theregulating height of the liquid level .is no longer produced by dis placement of the liquld by inserted reelain bodies but it is obtained without the use on such bodies in the numerous, much narrower, series-connected steam generating apparatus.

According to the invention electrically insulated tubular elements are inserted between the lower supply pipe common for each phase and the outer cup-shaped electrode, the li uid being supplied from below in a manner own per se, so that the voltage between phase and .zero point is not shortcircuited, as the supply tube common for each phase forms the zero point or is electrically connected with the same. The tubular insulating elements may be arranged either in the direction of the electrodes or transversely to the same. If the insulating tubes are mounted in the longitudinal direction'of the electrodes they serve to prevent short steam generators.

Several embodiments of the invention are illustrated in the accompanying drawings in Fi 1 shows in a longitudinalsection on line B of Fig.2 and Fig. 2 in cross section on line (i -D of Fig. 1 the improved boiler in which the serice-connected steam generators are mounted on insulating elements. p Fig. 3 shows how, these insulating elements get gradually shorter. .Fig. 4 shows in vertical section'and Fig. 5 in cross sectlon a boiler withtran s verse insulating elements.

Each of theconductors I, II, III of the and of, the

three phases of a polyphase net 1Is conducted over one row of series-connected steam generators, (Z d (F, d, d 11. More or less steam generators than shownmay be provided, at least two being however required according to the invention. The current flows through the inner electrode i of the steam generator d through the liquid f contained in this generator to the outer electrode a, thence through a metal bridge I) to the inner electrode 1' of the second steam generator (1 and so forth until its voltage on the crossconductor g which conneets 'the outer electrode of the extreme steam generator has become equal to zero. It is not absolutely necessary to lead the current first to the first inner electrode, it might be led first to the outer electrode, and through the liquid to the inner electrode. Whilst in the commonl used steam generators with only one single outer cup-shaped electrode the current was consumed at passing through the liquid enclosed between the only inner electrode and the only outer electrode of one phase, e. g. reduced to zero as regards voltage, the voltage E in the improved boiler is reduced in each of the series of n connected steam generators only of If, as shown with the voltage E into the third steam generator with the voltage and so forth. As the several steam enerators are ver long in proportion to t eir diameter and as, on the other hand, the efliciency increases with the higher liquid level the efliciency can be perfectly regulated. A further advantage is that the outer electrodes consist of seamless, comparatively thinwalled iron tubes which are much cheaper than one cup-shaped outer electrode of the boilers of known type, one such outer electrode being required for each phase.

The long and narrow steam generators of the improved boiler can be put together outside the boiler and inserted as a whole through the manhole, so that the diflicult insertion into and putting together in the boiler is avoided. From' the thin tubes a uniform steam generator can be produced which is adapted. for any voltages. For

I higher voltages it is merely necessary to insert a greater number of steam generators than for lower voltages, wherefrom results a considerable simplification of the project practicaljcarrying out of the boiler lant.

As s lown in Fig. 1 the cup shaped outer electrodes a, a a are mounted on insulating tubes 1' 1' 7* arranged in the direction of the longitudinal axis of the steam generators and designed to revent the current jumping over onto the supply pipe. which is common for each row of steam generators. As the" voltage decreases from steam generator to steam generator the length of the insulating tubes may decrease from steam generator to steam generator in accordance with the drop of" voltage, so that unnecessarily long insulating tubes are avoided.

As shown in Figs. -l and 5 only short insulating tubes are required if they are arranged transversely to the steam generators, as these tubes have to resist not to a voltage from the maximum value to zero value but only to the voltage The short insulating tubes A: form at the same time the common water supply pipe so that the separate lower pipe .2 shown in Fig. 1 is omitted. The water F in the boiler K is forced, in the usual manner, by a centrifugal pump p into the distributing conduit '0. As shown in Fig. 1 before the water in excess can enter into the first steam generator it flows off through a tubular socket 8 extending into the boiler K and comprising a regulatin valve It. This valve can be easily controlled from the outer side of the boiler by means of a hand wheel 71. so that the water level in the steam generators is either maintained on a predetermined height or drops and rises in accordance with the desired efiiciency. In all other types of electrically heated boilers it is also possible to regulate the water level in a similar manner, but in the improved boiler the regulation takes place at the inflow before the water has traversed a steam generator. The re ulation of the water supply is therefore in ependent of the uniform outflow holes of the steam generator.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electrically heated boiler the combination of steam generating apparatus arranged in the boiler, consisting of several outer vessels servingas electrodes and of inner electrodes inserted into said outer vessels, and means permitting of series-connecting the electrodes like a battery in such a manner that the 7 enter electrode of the first steam generatingrapparatus is electrically connected with the-inner electrode of the second apparatus and so forth.

2. In an electrically heated boiler the combination of steam enerating apparatus arranged in the ,1 or, consisting of several outer vessels as electrodes and of inner electrodes inserted into said oute'rvesscls, and means to combine in the boiler fin order to use" a polyphase current, several steam fneratin arati'is I tothe ge g (fp g hase number an series 'connected like a ttery the last electrodes of the several phasesbein electrically connected with one another to orm a zero vconductor.

3. In an electrically heated boiler the combination of steam generating apparatus arranged in the boiler, consisting of several battery, and of insulating tubes separating outer vessels serving as electrodes and of inner electrodes Inserted into said outer vessels of electrodes series-connected like a from one another the several steam generating apparatus.

4. In anelectrically heated boiler the combination of steam generating apparatus arranged in the boiler, consisting of several outer vessels serving as electrodes and of C inner filectrodes inserted into said outer vessels of electrodes series-connected like a battery, and of insulatih'g tubes separating from one another the several steam generating apparatus said insulating tubes forming at "the same time the connection of the several steam generatin apparatus with the common water supply pipe.

5. In an electrlcally heated boiler the combination of steam generating apparatus arranged in the boiler, consisting of several outer vessels serving as electrodes and of inner electrodes inserted into said outer vessels of electrodes series-connectedlike a battery, and of insulating tubes inserted between the several steam generating apparatus and forming the common water supply 35 tube. a Y 4 6. In an electrically heated boiler the combination of'steam generating apparatus arranged in the boiler, consisting of several outer vessels serving as electrodes and of 40 inner electrodes inserted into said outer vessels of electrodes serieS-connected'like a battery, and of insulating tubes connecting the several steam generating apparatus with the common water supply pipe and being of45 gradually decreasing height in accordance with the drop of voltage from steam generator to steam generator.

- of shutting ofi elementarranged in said outflow pipe and adapted to be operated from the outer side of the boiler by which shutting ofi' element the water supply can be regu'-- lated before the water flows into the steam generating apparatus.

' Signed at Berlin, Germany, this 31stday of December, 1925. v

EDUARD scHLEcK. 

